Single inner assembly wave interference silencer

Claim 2

An improved silencer assembly comprising: an outer tube, an inneR tube having opposite open ends thereon defining an inner acoustical path, a closure member connected between said outer tube and said inner tube to define a chamber at one end of said outer tube, a helical baffle formed between said inner tube and said outer tube defining an outer acoustical path between said inner tube and said outer tube having a length in excess of the length of said inner tube between said opposite open ends thereof, said outer acoustical path including an inlet at said chamber and an outlet at the outlet of said inner tube, said inner tube including a plurality of holes therein at one open end thereof located at said chamber for exhaust flow between said inner and outer acoustical paths to direct a predetermined portion of the exhaust flow from said inner tube through the inlet of said outer acoustical path and to provide a transparent area at a sound interaction point between the inner acoustical path through the inner tube and the outer acoustical path through the helical baffle to produce sound attenuation by wave interference with reduced turbulence produced noise at the sound interaction point between the inner and outer acoustical paths, said inner tube being imperforate between said plurality of holes and the opposite open end thereof to reduce exhaust flow pressure loss between the opposite open ends of said inner tube.

Claim 3

A wave interference silencer comprising: an outer tube having an end plate on either end thereof, means defining a bore in each of said end plates, an inner tube directed through one of said bores to be supportingly received thereon to locate said inner tube concentrically of and radially inwardly spaced to said outer tube, said inner tube being open throughout its length to define a primary exhaust flow path therethrough, a helical baffle located between said inner and outer tubes extending along the outer circumference of said inner tube, said helical baffle defining a curvilinear exhaust flow passage and a first acoustical path having an inlet and an outlet, said inner tube including a first set of holes therein acoustically communicating the inner tube with the inlet to said first acoustical path, said set of holes having a total cross-sectional flow area at the inlet of said first acoustical path substantially equal to the cross-sectional flow area through said inner tube and the cross-sectional flow area through said baffle passage to produce unrestricted noise interaction between said inner tube and said curvilinear exhaust flow passage, means defining an outlet from said inner tube at the outlet of said first acoustical path, said set of holes and inner tube outlet defining a second acoustical path through said inner tube having a length less than that of said first acoustical path to produce wave interference attenuation of sound frequencies in exhaust flow through said inner tube and said curvilinear exhaust flow passage, said inner tube being imperforate between said first set of holes and said inner tube outlet to maintain the primary flow of exhaust flow through said inner tube with reduced exhaust flow pressure drop therethrough.

Claim 4

A wave interference silencer comprising: an outer tube having an end plate on either end thereof, means defining a bore in each of said end plates, an inner tube directed through one of said bores to be supportingly received thereon to locate said inner tube concentrically of and radially inwardly spaced to said outer tube, said inner tube being open throughout its length to define a primary exhaust flow path therethrough, a helical baffle located between said inner and outer tubes extending along the outer circumference of said inner tube, said helical baffle defining a curvilinear exhaust flow passage and a first acoustical path having an inlet and an outlet, said inner tube including a first set of holes therein acoustically communicating the inner tube with the inlet to said first acoustical path, said set of holes having a total cross-sectional flow area at the inlet of said first acoustical path substantially equal to the cross-sectional flow area through said inner tube and the cross-sectional flow area through said baffle passage to produce unrestricted noise interaction between said inner tube and said curvilinear exhaust flow passage, means defining an outlet from said inner tube at the outlet of said first acoustical path, said set of holes and inner tube outlet defining a second acoustical path through said inner tube having a length less than that of said first acoustical path to produce wave interference attenuation of sound frequencies in exhaust flow through said inner tube and said curvilinear exhaust flow passage, said inner tube being imperforate between said first set of holes and said inner tube outlet to maintain the primary flow of exhaust flow through said inner tube with reduced exhaust flow pressure drop therethrough.

Claim 5

A wave interference silencer comprising: an outer tube having an end plate on either end thereof, means defining a bore in each of said end plates, a single inner tube directed through the length of said outer tube having portions thereon supportingly received within the end plate bores to locate said single inner tube concentrically of and radially inwardly spaced to said outer tube, said inner tube being open throughout its length to define a primary exhaust flow path therethrough, a helical baffle located between said inner and outer tubes extending along the outer circumference of said inner tube between the opposite end plates of said outer tube, said helical baffle defining a curvilinear passage and a first acoustical path having an inlet and an outlet, said inner tube including a first set of holes therein defining the inlet of a second acoustical path through said inner tube And communicating the inner tube with the inlet to said first acoustical path, said first set of holes having a total cross-sectional flow area at the inlet of said first acoustical path substantially equal to the cross-sectional exhaust flow area through said inner tube and the cross-sectional flow area through said curvilinear passage to produce unrestricted noise interaction between said inner tube and said curvilinear passage, means defining a second set of holes in said inner tube spaced downstream of said first set of holes therein to define the outlet of the second acoustical path through said inner tube, said second acoustical path having a length less than that of said first acoustical path, said second set of holes having a total cross-sectional flow area substantially equal to the cross-sectional flow area through said inner tube and said curvilinear passage, said second set of holes producing unrestricted noise interaction between said first and second acoustical paths to attenuate a predetermined range of sound frequencies, said inner tube being inperforate between said first and second set of holes to direct a primary flow of exhaust fluid through said inner tube with reduced exhaust flow pressure drop therethrough.

Claim 6

A wave interference silencer comprising: an outer tube having an end plate on either end thereof, means defining a bore in each of said end plates, a single inner tube directed through the length of said outer tube having portions thereon supportingly received within the end plate bores to locate said single inner tube concentrically of and radially inwardly spaced to said outer tube, said inner tube being open throughout its length to define a primary exhaust flow path therethrough, a helical baffle located between said inner and outer tubes extending along the outer circumference of said inner tube between the opposite end plates of said outer tube, said helical baffle defining a curvilinear passage and a first acoustical path having an inlet and an outlet, said inner tube including a first set of holes therein defining the inlet of a second acoustical path through said inner tube And communicating the inner tube with the inlet to said first acoustical path, said first set of holes having a total cross-sectional flow area at the inlet of said first acoustical path substantially equal to the cross-sectional exhaust flow area through said inner tube and the cross-sectional flow area through said curvilinear passage to produce unrestricted noise interaction between said inner tube and said curvilinear passage, means defining a second set of holes in said inner tube spaced downstream of said first set of holes therein to define the outlet of the second acoustical path through said inner tube, said second acoustical path having a length less than that of said first acoustical path, said second set of holes having a total cross-sectional flow area substantially equal to the cross-sectional flow area through said inner tube and said curvilinear passage, said second set of holes producing unrestricted noise interaction between said first and second acoustical paths to attenuate a predetermined range of sound frequencies, said inner tube being inperforate between said first and second set of holes to direct a primary flow of exhaust fluid through said inner tube with reduced exhaust flow pressure drop therethrough.

Claim 7

A wave interference silencer comprising: an outer tubular member having an end plate on opposite ends thereof, each of said end plates including a bore therethrough, a single inner tube supportingly received within each of said bores and extending axially through said outer tube in radially inwardly spaced relationship therewith, said inner tube having opposite ends thereon extending outwardly of said outer tube and adapted to be connected to conduits of an engine exhaust system, said inner tube being open throughout its length to define a primary exhaust flow path therethrough, a helical baffle located between said inner and outer tubes extending along the outer circumference of said inner tube along the length thereof between said outer tube end plates, said baffle defining a helically formed acoustical flow path having an inlet and an outlet end thereto, a first set of holes formed in said inner tube at the inlet to said helical acoustical path having a cross-sectional flow area substantially equal to the cross-sectional flow area through said inner tube, a second set of holes in said inner tube spaced axially from said first set of holes at the outlet of said helical acoustical path to define the outlet of a second acoustical path through said inner tube, said first acoustical path having a length greater than said second acoustical path, said first and second sets of holes intercommunicating said first and second acoustical paths to produce a predetermined wave interference attenuation of sound frequencies directed through said inner tube, said inner tube being imperforate between said first and second sets of holes to maintain an uninterrupted mass flow of exhaust through said inner pipe so as to reduce pressure drop between the opposite ends of said inner pipe during exhaust flow therethrough.

Claim 8

A wave interference silencer comprising: an outer tubular member having an end plate on opposite ends thereof, each of said end plates including a bore therethrough, a single inner tube supportingly received within each of said bores and extending axially through said outer tube in radially inwardly spaced relationship therewith, said inner tube having opposite ends thereon extending outwardly of said outer tube and adapted to be connected to conduits of an engine exhaust system, said inner tube being open throughout its length to define a primary exhaust flow path therethrough, a helical baffle located between said inner and outer tubes extending along the outer circumference of said inner tube along the length thereof between said outer tube end plates, said baffle defining a helically formed acoustical flow path having an inlet and an outlet end thereto, a first set of holes formed in said inner tube at the inlet to said helical acoustical path having a cross-sectional flow area substantially equal to the cross-sectional flow area through said inner tube, a second set of holes in said inner tube spaced axially from said first set of holes at the outlet of said helical acoustical path to define the outlet of a second acoustical path through said inner tube, said first acoustical path having a length greater than said second acoustical path, said first and second sets of holes intercommunicating said first and second acoustical paths to produce a predetermined wave interference attenuation of sound frequencies directed through said inner tube, said inner tube being imperforate between said first and second sets of holes to maintain an uninterrupted mass flow of exhaust through said inner pipe so as to reduce pressure drop between the opposite ends of said inner pipe during exhaust flow therethrough.

Claim 9

A wave interference silencer comprising: an outer tubular member having flat end plates on opposite ends thereof, each of said flat end plates including a bore therethrough, a single inner tube supportingly received within each of said bores and extending axially through said outer tube in radially inwardly spaced relationship therewith, said inner tube having opposite ends thereon extending outwardly of said outer tube and adapted to be connected to conduits of an engine exhaust system, said inner tube being open throughout its length to define a primary exhaust flow path therethrough, a helical baffle located between said inner and outer tubes extending along the outer circumference of said inner tube along the length thereof between said outer tube end plates, said baffle having the ends thereof in abutment with said flat end plates and defining a helically formed acoustical flow path having an inlet formed between first and second turns Of said baffle and an outlet, a first set of a plurality of rows of holes formed in said inner tube, at least one of said rows being located between one of said end plates and said first turn, the other of said rows being located between said first and second turns at the inlet to said helical acoustical path, said set of holes having a total cross-sectional flow area substantially equal to the cross-sectional flow area through said inner tube, a second set of holes in said inner tube spaced axially from said first set of holes at the outlet of said helical acoustical path to define the outlet of a second acoustical path through said inner tube, said first acoustical path having a length greater than said second acoustical path, said first and second sets of holes intercommunicating said first and second acoustical paths to produce a predetermined wave interference attenuation of sound frequencies directed through said inner tube, said inner tube being imperforate between said first and second sets of holes to maintain an uninterrupted mass flow of exhaust through said inner pipe so as to reduce pressure drop between the opposite ends of said inner pipe during exhaust flow therethrough.

Claim 10

A wave interference silencer comprising: an outer tubular member having flat end plates on opposite ends thereof, each of said flat end plates including a bore therethrough, a single inner tube supportingly received within each of said bores and extending axially through said outer tube in radially inwardly spaced relationship therewith, said inner tube having opposite ends thereon extending outwardly of said outer tube and adapted to be connected to conduits of an engine exhaust system, said inner tube being open throughout its length to define a primary exhaust flow path therethrough, a helical baffle located between said inner and outer tubes extending along the outer circumference of said inner tube along the length thereof between said outer tube end plates, said baffle having the ends thereof in abutment with said flat end plates and defining a helically formed acoustical flow path having an inlet formed between first and second turns Of said baffle and an outlet, a first set of a plurality of rows of holes formed in said inner tube, at least one of said rows being located between one of said end plates and said first turn, the other of said rows being located between said first and second turns at the inlet to said helical acoustical path, said set of holes having a total cross-sectional flow area substantially equal to the cross-sectional flow area through said inner tube, a second set of holes in said inner tube spaced axially from said first set of holes at the outlet of said helical acoustical path to define the outlet of a second acoustical path through said inner tube, said first acoustical path having a length greater than said second acoustical path, said first and second sets of holes intercommunicating said first and second acoustical paths to produce a predetermined wave interference attenuation of sound frequencies directed through said inner tube, said inner tube being imperforate between said first and second sets of holes to maintain an uninterrupted mass flow of exhaust through said inner pipe so as to reduce pressure drop between the opposite ends of said inner pipe during exhaust flow therethrough.